alternatives/LangSmith
LangSmith alternative

AIgateway: the best LangSmith alternative in 2026

The best LangSmith alternative in 2026 is AIgateway. LangSmith focuses on tracing and evaluating LangChain apps; AIgateway is a production inference gateway that ships observability, evals, caching, and a sub-account API on top of a 100+ model multi-modal catalog — without coupling you to LangChain.

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Feature comparison

AIgateway vs LangSmith

Side-by-side on the dimensions that move a production decision.

Feature
AIgateway
LangSmith
Works without LangChain
Yes — any HTTP client
Best with LangChain
Inference gateway
Yes — 100+ models
No — observability only
Caching + routing
Yes
No
Seat fees
None
Yes
Evals
Yes — binds to routing aliases
Yes — strong eval UX
Sub-account API
Yes
Limited

Feature comparison reflects public documentation as of 2026. LangSmith pricing shape: Seat-based with usage component.. Catalog: None — observes upstream providers..

Migrate in 5 minutes

Three steps. One base URL.

If you're on LangSmith through the OpenAI SDK, you're 90% of the way there. Change the base URL and the key.

STEP 01

Sign up for AIgateway

Create an account at aigateway.sh/signin and copy an sk-aig-... key from the dashboard.

STEP 02

Swap base URL + key

from openai import OpenAI

client = OpenAI(
    base_url="https://api.aigateway.sh/v1",
    api_key="sk-aig-...",
)
STEP 03

Ship

Request shape, response shape, streaming SSE — identical to OpenAI. Model slugs map 1:1 on shared providers. LangSmith users typically migrate in under 5 minutes.

4 other alternatives

Other LangSmith alternatives worth checking

Honest take: here are four other credible options. None ship the full multi-modal catalog + sub-accounts + evals under one key, but each has a legit wedge.

#2 — LLM router

OpenRouter

Text-LLM aggregator with ~300 model routes.

Closed source · ~300 text-only models.
Read the full OpenRouter comparison →
#3 — Governance gateway

Portkey

LLM gateway-as-a-service focused on governance and observability.

Partially open source · ~40 models, mostly text + some image.
Read the full Portkey comparison →
#4 — Observability proxy

Helicone

LLM observability proxy — strong at logging, not a routing layer.

Open source · Pass-through proxy — whatever providers you wire up.
Read the full Helicone comparison →
#5 — LLM router

Requesty

Cost-aware text-LLM router.

Closed source · ~50 text models.
Read the full Requesty comparison →
FAQ

Common questions about LangSmith alternatives

Is LangSmith open source?
No — LangSmith is a closed-source SaaS from LangChain, Inc. AIgateway is also closed-source.
Does LangSmith charge seat fees?
Yes — LangSmith's commercial tier is seat-based with a usage component. AIgateway has no seat fees; flat 5% at top-up.
Do I need LangChain to use LangSmith?
LangSmith works best inside LangChain apps. AIgateway is framework-agnostic — any HTTP client or the OpenAI SDK works.
Does LangSmith support non-text modalities?
LangSmith traces whatever your LangChain app calls. AIgateway natively supports text, image, video, voice, audio, music, and embeddings.
Can I run LangSmith on top of AIgateway traffic?
Yes — point your LangChain integration at https://api.aigateway.sh/v1 and let LangSmith trace normally.
Is AIgateway cheaper than LangSmith?
For most teams, yes — no seat fees, no per-event observability charges. Pay 5% at top-up, nothing else.
More alternatives

Switching from something else?

OpenRouter alternative →Portkey alternative →Helicone alternative →Requesty alternative →Braintrust alternative →LiteLLM alternative →Vellum alternative →Traceloop alternative →Langfuse alternative →Anyscale alternative →Together AI alternative →Fireworks AI alternative →